The Temple Thrombosis Research Center is a formally established research institute within the medical school dedicated to advancing our understanding of the etiology, pathogenesis, diagnosis and treatment of arterial and venous thrombosis. Investigators in this Center are examining the role of platelets, plasma coagulation factors, vascular wall cells, megakaryocytes and leukocytes in thrombogenesis. As normal biochemical and physiological mechanisms are elucidated, departures from these patterns of response provide the knowledge of pathological processes that are necessary for development of appropriate diagnostic tests. The increasing understanding of the abnormalities underlying the thrombotic process makes possible the rational development of therapeutic interventions to inhibit or prevent thrombogenesis in a vessel. Each project has the potential to indicate an appropriate inhibitory drug or other therapeutic approaches to prevent platelet aggregation, fibrin formation or the consequences of vessel wall injury, all of which contribute to the formation of an obstructing thrombus. The first objective is to understand the metabolism and eventually control stimulus-response coupling in platelets. The second objective is to study the interaction of plasma and platelet proteins with cells and surfaces in order to delineate mechanisms of the thrombotic process.